It is known to conduct fracturing or other stimulation procedures in a wellbore by isolating zones of interest, (or intervals within a zone), in the wellbore, using packers and the like, and subjecting the isolated zone to treatment fluids, including liquids and gases, at treatment pressures. In a typical fracturing procedure for a cased wellbore, for example, the casing of the well is perforated to admit oil and/or gas into the wellbore and fracturing fluid is then pumped into the wellbore and through the perforations into the formation. Such treatment opens and/or enlarges drainage channels in the formation, enhancing the producing ability of the well. For open holes that are not cased, stimulation is carried out directly in the zones or zone intervals.
The fracturing operations include a variety of downhole tools that include relatively fine tolerances for operation including shifting sleeves, ports and ball seats. The fluid arriving downhole should be free of solids or debris which could interfere with the tools.
Normally the fluids are solids free or intentionally contain specific and acceptable solid particulates such as frac sand and proppent. Unfortunately, reality is such that debris can also enter the system at the supply side including equipment breakdown or introduced during assembly. Equipment can include pumps and blenders with moving components subject to component wear and castoffs which can enter the fluid stream. Examples of some of the components that can enter the fluid stream include parts of turbine wheels, seals, seat retainers, check valve flappers, and union seals. Further, in the on-site coupling of frac fluid supply lines, debris such as mud and gravel, can be inadvertently introduced.